Impacts of fortified foods and supplement use on B-vitamin status in older adults: findings from the TUDA study

Sub-optimal status of one or more of the interrelated B-vitamins (folate, B12, B6 and riboflavin) is common among older adults1, and considerable observational evidence links low B-vitamin status (and/or elevated concentrations of the related metabolite, homocysteine) with a higher risk of agerelated diseases2,3. These nutrients are interlinked though their roles in one-carbon metabolism, but very few studies have investigated the major contributors to status of all four B-vitamins or the trends in B-vitamin biomarkers with advancing age. The aim of this study, therefore, was to investigate the contribution of fortified foods and supplements to dietary intakes and biomarkers of B-vitamins in older adults. From a total sample of community-dwelling older adults (n = 5,186; ≥ 60 years) initially recruited to the Trinity-Ulster-Department of Agriculture (TUDA) study from 2008–2012, an eligible subset (n = 953) was re-investigated between 2016 and 2019. Dietary intake was assessed using a 4-day food diary (over four consecutive days) in combination with a food-frequency questionnaire. Mean daily energy and B-vitamin intakes were calculated using a customised version of the nutritional software package Nutritics (V.4). Non-fasting blood samples were collected at initial sampling and at follow-up to measure corresponding B-vitamin biomarkers. Statistical differences between categories of fortified food consumption and supplement use were assessed using ANCOVA (with adjustment for relevant covariates), while relationships between dietary and corresponding biomarker variables were examined using Pearson correlation coefficients. As dietary intakes of fortified foods increased (from 0 to > 7 portions per week), biomarkers of each B-vitamin improved in a stepwise manner (P